Injection or transfer molding processes are commonly used to shape articles out of "plastic". Such articles can be formed from thermoplastic or thermosetting resins, the composition of which is formulated to provide properties that in many cases rival that of metal. The article shape is controlled by the configuration of the mold cavity, as is well known.
It is common for such articles to include electrical elements for one reason or another. Such elements ar placed in the mold cavity during manufacturing so that the elements become buried or surrounded by the inflowing resin. Necessarily, however, the wire leads, usually two or more of them, of such an element are left projecting or exposed, so that external electrical contact can be made to the element inside the molded article. A conventional method of doing this is to use a mold in which the leads stick out away from the mold cavity, and thus are not covered with resin when the element is otherwise covered.
An example of such an articles is a molded catcher assembly 26 of the type shown in U.S. Pat. No. 4,636,808. Such a catcher conveniently includes a resistive heater element, so that the temperature of both the catcher and the charge plate can be elevated, as is desired in ink jet printers.
Although such a method of molding the article is useful, the projection of the leads out of the molded article to a considerable extent can create a problem. That is, the leads are subject to being bent or broken, and cause the article to occupy substantially more volume than would be the case without the leads projecting away from the article. Furthermore, such leads do not necessarily occupy a fixed or consistent location, thus making further connection more difficult.
Therefore, prior to this invention there has been a need to mold the article so that the leads remain within the three-dimensional confines of the article, but without being covered by the resin. In other words, the leads must still be accessible for contact, e.g., by soldering, without taking up volume or space outside of the overall volume or space occupied by the article. However, any mold design that leaves all the leads within the intended three-dimensional confines of the article, and thus within the cavity of the mold, is in jeopardy of covering the leads with the resin and making them inaccessible.